This invention is related to an inventive baluster or spindle of synthetic stone material and the method of manufacturing the same. Specifically, the baluster or spindle is manufactured using an inventive molding method which includes the combined use of mesh sheets within the mold and agitation of the mold to produce a superior product.
The baluster or spindle disclosed herein is intended for use in a railing, where the baluster or spindle decoratively supports and separates an upper rail and a lower rail. The baluster is formed of a synthetic stone material which simulates marble, and is fabricated by casting in a mold. In use, the baluster is joined to the upper and lower rails by means of a conduit which is fitted within and extends through the top and bottom ends of the baluster. The conduit has ends which extend in a fitted manner through openings in the closed top and bottom ends of the baluster. The end portions of the conduit are received within openings in the lower surface of the upper rail and the upper surface of the lower rail.
The invention arose from the desire to produce a synthetic stone baluster or spindle in a manner which minimized the use of synthetic stone so to reduce manufacturing costs, yet produced a baluster which closely simulated a stone product in external appearance, performance, and weight.
A manufacturing method was developed to form the baluster or spindle by casting it in a mold which is agitated during the curing phase. The mold for a baluster includes an elongate, shaped body portion. The opposed ends of the mold are closed and flat so as to provide a baluster that has top and bottom surfaces which are planar and oriented perpendicular to the longitudinal axis of the baluster. Agitation of the mold consisted of a combination of rotation of the mold about its longitudinal axis (spinning) concurrent with rotation of the mold about an axis which is perpendicular to the longitudinal axis of the mold (rocking). Spinning and rocking the mold produced a finished product having a hollow interior, and an exterior which was highly dense, uniform, and of high surface quality.
An unsatisfactory result of this method were balusters having top and bottom surfaces which were, at best non-planar or recessed, or at worst completely open. Open ends prevented securement of the conduit within the baluster.
To correct this defect in the finished product, a thin, rigid mesh sheet was placed within the mold adjacent each end of the mold. During agitation, the mesh sheet provided a means by which the synthetic stone material could be retained against the interior surfaces of the ends of the mold.
The resulting baluster consisted of a hard outer shell having closed, flat top and bottom ends. Furthermore, only 1/4 as much simulated stone material was required to form baluster a baluster having closed ends when the mesh sheet was employed, resulting in substantial economic benefit to the manufacturer.